A solar cell module comprises a solar cell die soldered to a substrate having a plurality of electrical traces terminating in at least two power contacts output onto a surface of the substrate. A solar cell die housing, termed a cowling, is coupled to the substrate with a curable sealant such as a room temperature vulcanization (RTV) sealant. Curing of the sealant can be accelerated by application of heat, but the application of too much heat can degrade the bonding strength and change the properties of the RTV sealant. Also, excessive heat may expand the RTV rapidly, squeezing the RTV, leaking the RTV out to the cowling that may result in an electrical contact problem in addition to the leakage of the RTV.
After the solar cell die housing is coupled to the substrate, a power conductor is coupled to a power contact on the substrate, thereby electrically coupling the solar cell die to the power conductor via the power contact on the substrate. The temperature at the power contact during soldering can be as high as 220° C. for a tin/lead solder process, or higher for a lead-free process. If the substrate is cold, relative to the 220° C. solder temperature, then the resulting solder joint at the power contact can comprise a solder “cold-joint” that is subject to cracking and breaking. If the temperature of the solder at the power contact is held high long enough to overcome a cold-joint, then too much heat may be transferred to the substrate, thereby burning and degrading the RTV sealant that bonds the solar cell die housing to the substrate. Further, excessive heat applied to the substrate can result in increasing the size of solder voids in the solder joint between the solar cell die and the substrate.
To address these problems, it is desirable to control the temperature of the substrate in relation to the effect of temperature upon the RTV sealant in contact with the substrate and in relation to the temperature needed to make a high quality solder joint of the power conductor to the power contact on the substrate.